Balloon catheters have, over the course of the last few decades, found use in the diagnosis and treatment of many medical conditions. While different versions of these devices have been designed and constructed for use in many different body passages—such as the urinary tract, uterus and fallopian tubes and gastrointestinal tract—the intravascular use of balloon catheters is arguably their fastest-growing field of application. Thus, balloon catheters have been used in various angioplasty procedures, stent implantation, thrombus-crossing, embolic protection, and so on.
The inappropriate and undesirable formation of blood clots intravascularly may have severe pathological consequences, as a consequence of the disturbance of blood flow to vital organs and tissues such as the heart muscle and brain. In extreme cases, total occlusion of the afferent arteries may lead to ischemic damage which, in the case of the heart, may manifest itself clinically in the form of myocardial infarction. Similarly, the local production of thrombi in the cerebral vessels or the deposition therein of thrombotic emboli may lead to cerebral infarcts. In both cases, serious morbidity and death are common consequences. It has been estimated, for example, that emboli arising from atherosclerotic plaques of the carotid artery cause approximately one quarter of the 500,000 strokes that are recorded annually in the United States.
Several different medical and surgical approaches aimed at removing thrombotic and embolic material from blood vessels have been proposed and attempted. One such approach requires the injection of thrombolytic agents. Alternatively or additionally, a variety of balloon catheter systems have been used to both expand blood vessels that have become narrowed due to thrombus formation or deposition and, in some cases to collect detached thrombotic material and remove same from the body.
One example of a balloon catheter system that has been designed for use in removing thrombotic material and other intravascular particulate matter from the body is that disclosed in U.S. Pat. No. 4,762,130 (Fogarty). While several different embodiments of the catheter are described in the patent, a feature common to all of these embodiments is that a balloon is advanced into the region of the thrombus to be treated and then expanded into a helical or spiral configuration, thereby engaging said thrombus within the spiral channels of the inflated balloon. The spiral balloon is then withdrawn from the body with the thrombus still attached thereto. A particular disadvantage of this prior art system is that the catheter is usually inflated distally to the thrombus (or other particulate matter) and is then pulled back in order to facilitate collection of the thrombotic material by the balloon. This procedure can be traumatic for the blood vessel. Furthermore the balloon does not always completely seal the vessel and some of the debris escapes into the blood stream and is not removed.
A further key problem associated with the aforementioned prior art system is the fact that during balloon inflation, the blood flow through the vessel is blocked. Indeed, in many balloon catheter systems, the volume taken up by the balloon when inflated is problematic. In addition, many existing catheter balloons, even when in their deflated state present an unacceptably large cross-sectional profile, thereby causing problems in the insertion and maneuvering of the catheter within the vasculature.
It is a purpose of the present invention to provide a novel balloon catheter system that presents both a small cross-sectional profile when the balloon is deflated, and which allows blood flow therearound, even when the balloon is fully inflated.
It is a further purpose of the invention to provide a system that may be used for trapping and retaining particulate matter and safely removing said matter from the body.
It is a still further purpose of the invention to provide a balloon catheter system that overcomes the problems and disadvantages associated with prior art devices.
Further objects and advantages of the present invention will become apparent as the description proceeds.